Transgenic plants are now common in the agricultural industry. Such plants express novel transgenic traits such as insect resistance, stress tolerance, improved oil quality, improved meal quality and heterologous protein production. As more and more transgenic plants are developed and introduced into the environment, it is important to control the undesired spread of transgenic traits from transgenic plants to other traditional and transgenic cultivars, plant species and breeding lines.
While physical isolation and pollen trapping border rows have been employed to control transgenic plants under study conditions, these methods are cumbersome and are not practical for many cultivated transgenic plants. Effective ways to control the transmission and expression of transgenic traits without intervention would be useful for managing transgenic plants.
One recent genetic approach involves the production of transgenic plants that comprise recombinant traits of interest linked to repressible lethal genes. See, WO 00/37660. The lethal genes are blocked by the action of repressor molecules produced by repressor genes located at a different genetic locus. The lethal phenotype is expressed only if the repressible lethal gene construct and the repressor gene segregate after meiosis. This approach reportedly can be used to maintain genetic purity by blocking introgression of genes from plants that lack the repressor gene.